Apparatus for sectionally delivering a web from a storage roll

ABSTRACT

An apparatus for delivering a web intermittently from a web storage roll so that successive sections of the web may be cut into sheets for use as needed is made to enable fast operation without over-tensioning the web at the start or over-accumulating it at the end of a web feeding operation, by providing a carriage on which the roll is rotatably supported and which is displaceable horizontally relative to the web feeding means, as by being mounted through wheels for free movement along horizontal rails, and applying to the carriage, as by springs or a special counterweight system, a force urging it in the direction away from the web-feeding means so as to counteract yieldably the tension applied to the web leading from the roll when the feeding means is operated. That tension displaces the carriage and roll toward the web feeding means until, by accompanying increases of the counteracting force and the unwinding rotation of the roll, an equilibrium position is reached; and when the web feeding is stopped the force applied to the carriage moves it and the roll back to their idle position.

United States Patent [191 Lemmen APPARATUS FOR SECTIONALLY DELIVERING A WEB FROM A STORAGE ROLL [75 Inventor: Conrardus Johannes Gerardus Lemmen, Baexem, Netherlands [73] Assignee: Oc-vander Grinten N.V. Venlo,

Netherlands 22 Filed: March 9,1971 21 Appl.No.: 122,351

[30] Foreign Application Priority Data March 10, 1970 Netherlands ..7003386 [52] US. Cl. ..242/75, 242/55 [51] Int. Cl. ..B65h 23/08 [58] Field of Search....242/75, 75.1, 75.3, 75.4, 67.2, 242/673 R, 55

[ 1 Feb. 27, 1973 Primary Examiner-George F. Mautz Assistant ExaminerEdward J. McCarthy Att0rneyAlbert C. Johnston [5 7] ABSTRACT An apparatus for delivering a web intermittently from a web storage roll so that successive sections of the web may be cut into sheets for use as needed is made to enable fast operation without over-tensioning the web at the start or over-accumulating it at the end of a web feeding operation, by providing a carriage on which the roll is rotatably supported and which is displaceable horizontally relative to the web feeding means, as by being mounted through wheels for free movement along horizontal rails, and applying to the carriage, as by springs or a special counterweight system, a force urging it in the direction away from the web-feeding means so as to counteract yieldably the tension applied to the web leading from the roll when the feeding means is operated. That tension displaces the carriage and roll toward the web feeding means until, by accompanying increases of the counteracting force and the unwinding rotation of the roll, an equilibrium position is reached; and when the web feeding is stopped the force applied to the carriage moves it and the roll back to their idle position.

6 Claims, 3 Drawing Figures APPARATUS FOR SECTIONALLY DELIVERING A WEB FROM A STORAGE ROLL This invention relates to an apparatus for sectionally, or piecewise, delivering a web of sheet material from a web storage roll by unreelingof a type which comprises conveying members acting on the web for intermittent feeding of the web, a support system in which the roll is rotatably supported, and means resisting rotation of the roll.

Such devices are often used where a rolled web is to be cut into sheets.

Whenever a sheet is needed, a web section of desired length is unreeled and subsequently cut off. Due to the intermittent feeding of the web, in which the roll is repeatedly started, tension occurs in the web. Especially when the storage roll is relatively heavy and/or the driven speed of the web is comparatively high, it is important to keep the tensionfrom reaching a level at which the web would tear.

On switching off the drive to the web, the roll may not stop immediately, thus causing more web material to be unreeled than needed. To avoid difficulties when the drive on the web is started again, the excess unreeled material should be prevented from being accumulated in an undesirable manner.

Expedients for absorbing shocks on the web and preventing objectionable accumulation of web material are known. For example, use is made of a movable accumulator roll resting in the web between the storage roll and a conveyor roll, thus taking up a quantity of web material. In the use of such a device, when the drive to the web is started the web material is initially drawn off at the driving speed, though the storage roll speeds up only gradually under the influence of the weight of the accumulator roll. Upon switching off the drive to the web, the accumulator roll moves to take up the excess material unreeled from the storage roll.

Such known expedients do not satisfactorily fulfill the needs, as the apparatus is rather complicated, and often it is difficult to thread the web from a new storage roll properly through the device. Moreover, particularly on long standing, there is a tendency for that part of the web subject to the weight of the accumulator roll to deform, for instance owing to absorption or loss of moisture.

The object of this invention is to provide an improved apparatus, or device, which will serve more satisfactorily than known devices for delivering a web intermittently in sections, or piecewise, from a web storage roll.

According to the present invention, the supporting system of the storage roll is made to be slidable on horizontally extending supports, and means are provided for acting on the supporting system so as to counteract sliding movement of the roll in the direction toward the web conveying members. In an apparatus embodying this construction, when the drive to the conveying members is switched on, the section of web material to be used, as by being cut off to form a sheet, is delivered at first by drawing forward the material that extends from the storage roll and at the same time sliding that roll forward toward the web feeding or conveying members, during which sliding movement the unreeling of the storage roll speeds up gradually; and when the tension in the web and the force of the means counteracting sliding of the roll toward the conveying members become equal, the roll will have reached full unwinding speed and will slide no further. Thereafter, when the drive. of the web is switched off, the said means acting on the roll supporting system will return the storage roll to its initial position while keeping the web under tension, thus accumulating excess unreeled web material in the space between the forward delivery position and the idle position of the roll.

A particular advantage of the invention is that the accumulative efiect of the apparatus is increased as the diameter of the storage roll becomes larger; this gives almost optimum adaptation of the accumulative effect to the diameter and weight of the roll.

Compared to prior art devices, the apparatus accord-- ing to the invention has the additional advantages of requiring less space and of permitting the lead of the web between the storage roll and the conveying members to extend straight, as a result of which no deformation occurs in it on standing; also the leading edge of the web of a new roll can easily be threaded into working position.

According to a further feature of the invention, the means which counteract forward sliding movement of the roll supporting system is advantageously constructed sothat the force with which it counteracts such movement increases as the supporting system is moved nearer to the conveying members. In this way the interval, or distance of roll travel, at which the lateral movement of the supporting system towards the conveying members ceases is controlled more accurately for a given speed of the conveying members, and the supporting system is not accelerated backward too much when the drive to the conveying members is switched off, thus avoiding need for additional damping and avoiding any strong shocks on movement limiting stops.

Preferably the counteracting means consists of one or more springs acting on the supporting system, for instance on either side of the web.

The foregoing and other objects, features and advantages of the invention will be further evident from the following detailed description and the accompanying illustrative drawing of a preferred embodiment of the invention.

In the drawing:

FIG. 1 is a schematic longitudinal section of an apparatus embodying the invention;

FIG. 2 is a partial cross section along the line IIII' of FIG. 1; and

FIG. 3 is a schematic view of a special embodiment of the means for counteracting sliding of the roll supporting system.

Referring to FIG. 1, a storage roll 1 comprises a quantity of continuous web material wound around a roll core 2, journals 3 of which are located in bearing blocks 4. The web material may be, for example, a paper web from which sheets are to be cut for use in photoprinting work. The blocks 4 may consist of, or have bearing surfaces lined with a plastics friction pad such as Vulkolan (trade mark), a linear polyurethane available from Farbenfabriken Bayer A.G., so that there will be a frictional resistance to free rotation of the web storage roll.

The blocks 4 are fixed to angled plates 5 which are rigidly connected together by means of connecting rods 6, thus forming a movable unitary supporting system, or carriage, for the web storage roll.

This supporting system is provided with wheels 7 and 8 respectively, which may be joumaled on the ends of the connecting rods and are situated and guided in rails 9, The rails extend in horizontal direction and are fixed to a machine frame 10 at opposite sides of the roll station. FIG. 2 illustrates the structure at one side; that at the other side is similar.

Furthermore, to each plate 5 is attached one end of a tension spring 1 l, the other end of which is secured to a pin 12 fixed to frame 10.

The roll supporting system, or carriage, has a normal backward position relative to the rails 9 and frame 10, in which it rests against some stops 13.

Preferably the springs 11 are designed so that they exert a slight force to hold the supporting system against these stops.

A lead 14 of the web of sheet material wound on the storage roll 1 extends from the roll forwardly into engagement with conveying members which, in this embodiment, consist of web driving rollers 15 and 16. These rollers may be covered with an elastomer such as rubber, in order to hold the web resiliently. At least one of them is driven intermittently by suitable rotary drive means (not shown) so that they will advance the web to a handling station where the web is, for instance, cut into sheets.

When the drive to the rollers 15 and 16 is switched on, the rollers advance the web between them and almost instantly reach their full web driving speed. The web material drawn between the rollers is at the outset of their operation obtained primarily by forward displacement of the web lead 14 and corresponding forward sliding movement of the supporting system and roll 1, to the right as seen in FIG. 1', under the tension applied to the web lead 14. As the roll carriage is pulled forward, the springs 11 exert a continually increasing counteracting force, and when this spring force becomes equal to the pull to the right on the web, transmitted via the journals 3 and bearing blocks 4, the supporting system stops sliding and stands still. From this time on, further advance of the web is completely provided by unwinding rotation of the storage roll 1 which, in the course of being slid toward the rollers 15 and 16, has gradually reached the required speed. Thus the web lead 14 reaches the desired transport speed very rapidly, whereas the storage roll only gradually acquires the corresponding rotational speed. This prevents too high a tension from occurring in the web lead extending from the roll to the web driving rollers.

When the driving action of rollers 15 and 16 is stopped, with stopping of the forward pull on the web lead 14, the springs 11 draw the supporting system and the roll thereon backward, to the left as shown in FIG. 1, towardtheir normal, or idle, position determined by the location of the stops 13. Thus, the web lead 14 extending between the storage roll 1 and the web driving rollers 15, 16 is continuously kept tensioned, and the web material which continues to enter this lead after the stopping of the web drive, due to the rotational momentum of the storage roll 1 which does not stop immediately, is taken up in the lead 14 by the lengthening of the distance between the roll and the rollers which occurs as the roll is moved backward. In this way any undesirable accumulation of the web material prevented.

The construction of apparatus embodying the invention may be varied in many ways. The roll supporting system may, for instance, be made in the form of a carriage sliding on a rail, or may comprise a telescopic rail to a sliding part of which are attached bearing blocks holding journals of the storage roll core.

Instead of bearing blocks made from or lined with a friction material, normal bearings giving less friction may also be used. In such a case the means counteracting the rotation of the roll may comprise braking means which, for example, act on the journals of the roll.

Sliding of the supporting system and storage roll may also be counteracted by use of a weight connected with the supporting system via a string. In FIG. 3, such an embodiment is represented schematically. In this figure a roll supporting system 17 is coupled, via string 18, to a drum 19 which is set on a rotatable bearing shaft 20. Shaft 20 also carries an eccentric or cam-shaped pulley 21 over which passes a string 23 loaded with a weight 22.

Upon moving system 17 to the right, as shown in FIG. 3, the radial distance between cable 23 and shaft 20, as determined by the radius of the surface of pulley 21 at the point where it is lifting the cable, will steadily increase so that the moment caused by weight 22 increases and thus the force acting to counteract movement of system 17 to the right is also and correspondingly increased.

What is claimed is:

1. In apparatus for sectionally delivering a web of sheet material from a roll of the web, including support means on-which the roll is rotatably supported, web feeding means to engage the web lead extending from the roll and operable intermittently to advance the web from said lead section by section, and means imposing resistance to rotation of the roll, the improvement which comprises means mounting said support means for displacement horizontally to and fro relative to said feeding means, so that said support means and the roll thereon may be displaced in the direction toward said feeding means by the tension applied to said web lead by the operation of said feeding means, and means for applying to said support means in counteraction to said tension when said support means and the roll .thereon are so displaced a force in the direction away from said feeding means sufficient to cause unwinding rotation of said roll.

2. Apparatus according to claim 1, said force applying means being attached to said support means and being operative to increase the magnitude of said force as said support means is displaced nearer to said web feeding means, so that during operation of the latter said support means and the roll thereon will reach and stand in a forward working position at which said tension and said force are in equilibrium.

3. Apparatus according to claim 2, said force applying means comprising at least one stretchable spring acting on said support means.

4. Apparatus according to claim 2, said force applying means comprising a counterweight acting on said support means through an eccentric pulley system.

5. Apparatus according to claim 1, said support means comprising a wheeled carriage having thereon reach and stand in a forward working position at which said tension and said force are in equilibrium, and stop means engaged by said carriage at a position thereof away from said feeding means to limit the backward movement thereof by said force applying means when said feeding means is inactive.

6. Apparatus according to claim 5, said bearing blocks including means for imposing frictional resistance to rotation of said journals. 

1. In apparatus for sectionally delivering a web of sheet material from a roll of the web, including support means on which the roll is rotatably supported, web feeding means to engage the web lead extending from the roll and operable intermittently to advance the web from said lead section by section, and means imposing resistance to rotation of the roll, the improvement which comprises means mounting said support means for displacement horizontally to and fro relative to said feeding means, so that said support means and the roll thereon may be displaced in the direction toward said feeding means by the tension applied to said web lead by the operation of said feeding means, and means for applying to said support means in counteraction to said tension when said support means and the roll thereon are so displaced a force in the direction away from said feeding means sufficient to cause unwinding rotation of said roll.
 2. Apparatus according to claim 1, said force applying means being attached to said support means and being operative to increase the magnitude of said force as said support means is displaced nearer to said web feeding means, so that during operation of the latter said support means and the roll thereon will reach and stand in a forward working position at which said tension and said force are in equilibrium.
 3. Apparatus according to claim 2, said force applying means comprising at least one stretchable spring acting on said support means.
 4. Apparatus according to claim 2, said force applying means comprising a counterweight acting on said support means through an eccentric pulley system.
 5. Apparatus according to claim 1, said support means comprising a wheeled carriage having thereon bearing blocks which receive journals on the ends of the core of the web roll, said mounting means including horizontally extending rail means supporting the wheels of said carriage so that said carriage is freely movable therealong, said force applying means comprising spring means or counterweight means connected to said carriage and operative to increase the magnitude of said force as said carriage is moved nearer to said web feeding means, so that during operation of the latter said carriage and the roll thereon will reach and stand in a forward working position at which said tension and said force are in equilibrium, and stop means engaged by said carriage at a position thereof away from said feeding means to limit the backward movement thereof by said force applying means when said feeding means is inactive.
 6. Apparatus according to claim 5, said bearing blocks including means for imposing frictional resistance to rotation of said journals. 